George Fisher Mine

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Mine TypeUnderground
  • Zinc
  • Lead
  • Silver
Mining Method
  • Sub-level open stoping (SLOS)
Production Start... Lock
Mine Life2044
ShapshotThe George Fisher mine is part of the Mount Isa Zinc Operation.

At George Fisher Mine, capital projects are focused on the ventilation and cooling of new mining blocks to support increased production in the future.
Related AssetMount Isa Zinc Operation


Glencore plc. 100 % Indirect



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Deposit type

  • Breccia pipe / Stockwork


George Fisher Mine (previously Hilton mine) is an underground zinc-lead-silver mine. It has two separate mining areas. The older Hilton mine is now known as George Fisher South and the newer mining area is George Fisher North (previously Hilton North).

The George Fisher orebody is an economic sulphide mineralisation. It is distinct from the nearby Mount Isa deposit due to its lack of breccia-hosted copper mineralisation. The deposit is composed of a series of 11 stratiform orebodies striking near N-S and dipping west between 30°-90°.

Lead-zinc-silver mineralisation occurs in galena and sphalerite-rich bedding parallel horizons in dolomitic and variably carbonaceous pyritic shales and siltstones. Orebody and structural interpretation, modelling and classification of the mineral resource was completed on the basis of additional geological information and improved systems.



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Mining Methods


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Crushers and Mills

Milling equipment has not been reported.


Some of the ore at the Zinc-Lead Concentrator is processed through a SAG Mill, however a pre-concentrating stage called the Heavy Medium Plant (HMP) is employed for most of the ore. The HMP utilises the large differences in densities between the valuable zinc- lead minerals (generally heavy material) and the waste minerals (typically lighter silica material) for separation. Ore is fed into Dense Medium Cyclones (DMC) that operate at a set density. This density is achieved by adding certain quantities of ferrosilicon to the cyclone. The material lighter than the target density will exit through the top of the cyclone and into the reject pile whilst the heavier material will report to the underflow of the cyclone and feed the Zinc-Lead Concentrator.

The ore that is processed through HMP is subsequently fed to Rod mills for the first stage of grinding.

To separate the valuable minerals from the waste, it is necessary to grind the rocks to 0.15 millimetres in diameter in the copper stream and 0.075 millimetres in diameter in the zinc-lead stream. The SAG and Rod Mills cannot grind to this size in one pass, so further grinding using Ball Mills is required.

To ensure that rocks are not ground up too fine, the Ball Mills are operated with "classifiers". A classifier literally separates (classifies) different particles according to size and removes fine particles from the circuit and sends them for downstream processing while sending large particles back to the mill for further grinding.

The classifiers which are used are called Hydrocyclones and get their name because the slurry is forced to spin (like a cyclone) inside the equipment. Large particles in the slurry are thrown to the outside of the Hydrocyclone as the slurry spins and exits through the bottom (underflow), while fine particles get dragged into the middle and exit through the top of the Hydrocyclone (overflow). In this way, coarse and fine particles are separated.

Although the valuable minerals are separated from the waste, even at these sizes the sphalerite (zinc) and galena (lead) minerals are not separated from each other, and so cannot be sent to a smelter. To separate them further, the Zinc-Lead Concentrator needs to grind down the ore to 0.008mm in diameter. This is done by using the lsaMill™Technology. lsaMills™are used in both the lead and zinc circuits.



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Combined production numbers are reported under Mount Isa Zinc Operation

Operational metrics

Ore tonnes mined 000000002.9 Mt

Production Costs

Commodity production costs have not been reported.

Heavy Mobile Equipment


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AV - Autonomous


Mine Management

Source Source
Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required May 15, 2024
....................... Subscription required ....................... Subscription required Subscription required May 15, 2024
....................... Subscription required ....................... Subscription required Subscription required May 15, 2024
....................... Subscription required ....................... Subscription required Subscription required May 15, 2024

Total WorkforceYear
Subscription required 2023
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Subscription required 2021
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Subscription required 2019
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Subscription required 2017
Subscription required 2016

Aerial view:


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